I just got done prepping and sealing off my grow closets in my garage. I have 2 rooms both 4x4. For my out flow of air I have a 180cfm squirrel cage fan ( in each room ) with 4in ducts connected to a carbon filter venting in my attic. For my inflow of air I was thinking a re routing a ac duct line (main line goes right over closets in attic) directly into my rooms. Do you think this is a good idea? Any feedback would be appreciated